We plan to investigate a number of time dependent reactions of fundamental importance to the viability of the lens. (1) It has been shown that the transformation of the alpha crystallin gene products, the A2 and B2 polypeptides to A1 and B1 chains involves a specific phosphorylation reaction which is cAMP dependent. The elucidation of the chemistry of the phosphorylation and the purpose of this post-translational reaction will be explored. (2) Investigation of the phosphorylation of the lens epithelial cells and changes in phosphorylation pattern with development will be undertaken. The objective is to find phosphorylation reactions associated with the differentiation of the epithelial cell into a fiber cell. (3) There is evidence that there is a change in the calcium dependent ATPases controlling intracellular Ca levels in the epithelial cell and the fiber cells. This observation will be confirmed and explored further. (4) It has been demonstrated that the 43,000 dalton polypeptide range fraction which accumulates with age in the human lens is generated by the formation of covalent non-disulfide linkages between the crystallin polypeptide chains. The elucidation of the linkage between such chains will be investigated. (5) Preliminary experiments suggest that there may be an intra-chain disulfide in gamma crystallin. This will be confirmed and experiments will be designed to determine its function.